What you need is the magic incantation with which you can send an HTTP request to a web server from a Windows (or ACP) script. No need for an executable, just use the Microsoft "ajax" object in the OS (you could use an executable via ACP's ShellExecute() but that would be really crude!). Here you go (written to run inside ACP's console, not via the Windows shell/CMD window). Load this into ACP's console and press Run. This is not tested:

Code:
//
// Test James Cottle AAVSO shutdown
//
// R. Denny 01-Jul-2014
//
var IP = "192.168.1.30";
var USER = "admin";
var PASS = "aavso";
//
// Call to shut down. Returns the text coming back from the web server, or if
// not OK (200) then returns the numeric error code and error text coming back
// from the server.
//
function doShutdown()
{
    var cmdline = "run010=run";
    var http = new ActiveXObject("MSXML2.XMLHTTP");
    http.open("GET", "http://" + IP + "/script?" + encodeURI(cmdline), false, USER, PASS);
    http.send();
    if(http.status == 200) {
        return http.responseText;
    } else {
        return http.status + " " + http.statusText;
    }
}
    
function main()
{
    try {
        Console.PrintLine(doShutdown());
    } catch (ex) {
        Console.PrintLine("Error: " + ex.Message);
    }
}